000
FXUS61 KOKX 221451
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1051 AM EDT Tue Aug 22 2023
.SYNOPSIS...
High pressure will build from the west through Wednesday. A
frontal system will then impact the area from Thursday into
Friday. A weak cold front will pass through late Saturday, with
Canadian high pressure building in behind it for early next
week.
&&
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Some high level clouds will work offshore this morning with
mostly sunny skies on tap today. N flow gusting to 20-25 mph
early will continue to usher in a cooler air mass, with high
temps at least a good 5-10 degrees cooler than those of Mon,
mainly 75-80.-- End Changed Discussion --
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
Diminishing N-NE flow will continue tonight under mostly clear
skies. Blyr could decouple late inland and across eastern Long
Island, with lows there in the upper 40s/lower 50s. Elsewhere,
low should range form the mid/upper 50s most elsewhere, to the
lower 60s in/just outside NYC. Slightly cooler highs expected
for Wed, with mid/upper 70s. As the high slides to the north,
mainly light NE winds should veer E and then SE through the day,
and then S Wed night. The air mass will modify slightly in the
return flow, with lows from the mid 50s to mid 60s.
For Thu, NAM may be too fast/aggressive with the approaching
frontal system, while the GFS may be too slow. Blended the two
to show gradually increasing shower chances from W-E, possibly a
late day tstm west of NYC. Temps under cloud cover and possible
precip should be even cooler, with highs from the upper 60s to
mid 70s.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Persistent NE troughing returns with a series of weak shortwaves
tracking through the region to end the week, with mean
troughing for the weekend into early next week. Meanwhile, the
anomalously strong Central and Southern US subtropical ridge
will gradually weaken and retrograde to the SW.
At the surface, weak low pressure currently over the foothills
of the Rockies, will gradually round the flattening central US
ridge during the mid week in response to shearing PAC shortwave
energy rounding the ridge. Its associated warm front approaches
the region Thu night with surface low pressure likely tracking
over the region Friday, and then east Friday Night.
Exact strength/track of the surface low will be refined, but
some ingredients to work with for heavy downpours during this
time period, in terms of subtle shortwave forcing, moisture
convergence with a modestly strong LLJ developing ahead of low
pressure, interacting with edge of instability gradient to the
SW and subtropical moisture from once Pacific tropical cyclone
Hilary rounding the ridge into the region. GEFS/GEPS/ECMWF
depict a 20-40% chance for 1" of rain in 24 hrs, with CSU MLP
and WPC indicating a marginal risk of excessive rainfall. At
this point any severe threat appears to be limited, with high
shear in an elevated CAPE environment but with a strong 700-900
cap. The details will ultimately be contingent on strength/track
of surface wave, but overall pattern is limiting.
The surface wave likely passes through on Friday, with an
attendant cold front sweeping through late in the day. Weak high
pressure builds in Fri night/Sat, before next shortwave and
weak cold front approaches and cross Sat aft/eve. Perhaps a few
showers with this front. Canadian high pressure builds in for
Sunday and Monday, with temps running a few degrees below
seasonable for late August.
Swells from tropical cyclone Franklin will likely build early
next week, with increasing potential for high surf and
dangerous rip currents. Monitor
https:/www.weather.gov/okx/tropical for the latest NHC
forecasts on this tropical system and others.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
Canadian high pressure builds in through tonight.
VFR. NNE winds 10-15G17-20kt through 18-20z. Winds slowly weaken
this evening and the direction may veer to the ENE-E for coastal
terminals towards sunset (KJFK, KISP, KBDR, and KGON). Winds go
back to the NNE overnight and will remain light.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Gusts may linger a few hours longer than indicated in the TAF.
Winds generally left of 030 true, but may waver around 030-040
between this afternoon and early evening for KLGA. Winds at KJFK
could briefly shift to the E around 00z.
OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY...
Wednesday: VFR. NE/E winds, becoming S.
Thursday/Friday: Chance of shwrs and tstms. MVFR or lower
possible at times. S/SE winds 15-20g25kt Thu PM, possibly into
Fri AM.
Saturday: VFR.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
SCA remains in effect for the ocean waters E of Moriches Inlet
this morning. Still seeing winds gusting close to 25 kt at a
mesonet site on Block Island, and seas at buoy 44097 to the SE
are running higher than fcst, so think some 5-footers may
briefly clip the waters S of Montauk early this morning.
Can`t rule out an occasional near shore gust close to 25 kt in
NY Harbor this morning and early afternoon as well. Otherwise,
sub-SCA cond expected to continue into Thu AM.
Strengthening SE-S flow ahead of an approaching frontal system
late Thu into Fri morning will likely develop SCA conditions on
the ocean and possibly all waters. Low prob of a short period of
gale force gusts Thu eve/night. Ocean seas should quickly
respond to 5-8 ft during this time in response, and may remain
elevated at SCA levels into early Saturday.
Thereafter, sub SCA conditions expected for the weekend on all
waters, with a weak cold frontal passage late Sat/Sat night,
followed by building Canadian high pressure.
&&
.HYDROLOGY...
A frontal system will bring potential for a period of downpours
and embedded thunderstorms late Thu into Fri. There is a low
threat for localized flash flooding based on the synoptic setup
and environment.
&&
.TIDES/COASTAL FLOODING...
-- Changed Discussion --
A low rip current risk continues for all Atlantic-facing beaches
today and Wednesday with surf height under 2 ft.
A high risk of rip current development is likely from late day
Thu into Fri with 5+ ft southerly wind waves.
Swells from tropical cyclone Franklin will likely build early next
week, with increasing potential for high surf and dangerous rip
currents.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until noon EDT today for ANZ350.
&&
$$
UPDATE...DW
AVIATION...DS/NV